Assessment of a Text Message–Based Smoking Cessation Intervention for Adult Smokers in China

Key Points Question What are the effects of a behavior change theory–based smoking cessation intervention using personalized text messages? Findings In this randomized clinical trial of 722 current smokers in China, participants who received the behavior change theory–based smoking cessation intervention using personalized text messages had a 6-month quit rate that was twice that of participants who received an intervention using nonpersonalized text messages. Meaning These findings provide new evidence supporting the utility of mobile health methods for smoking cessation.

1. Try not to smoke after today, not even a puff.
2. Please remove all the tobacco products from your possession.
3. Avoid drinking alcohol or attending smokers party. Increase severity and susceptibility L-R and L-SS L-R: After you maintain abstinence for a period of time, you will feel refreshed and energetic. Keep trying, you will feel it soon.

L-SS:
Even occasional smoke can cause serious health problems; therefore, we need to quit smoking, not reduce the amount of smoking.
L-RR: Quitting smoking will not cause your body any problems; the possible discomfort in the early weeks of quitting is called "withdrawal symptoms," which can disappear after a few weeks.

L-EE:
You may have noticed some improvements in your body, such as increased appetite and easy breathing, which are the benefits of quitting smoking.

Development of the intervention framework
The first stage was to develop the theoretical framework of the intervention based on the transtheoretical model (TTM) and protection motivation theory (PMT). Both models have been independently applied to health behaviour change interventions [1][2]. For the TTM, given the systematic relationship between the stages and processes of change, several strategies were used to strengthen behaviour change and/or to achieve the next stage. On the prequit date, messages related to consciousness raising, dramatic relief, and environmental reevaluation were provided to smokers with weak quitting intention. Messages related to stimulus control, self-liberation, and reinforcement management were provided to smokers with strong quitting intention. On the early quit and late quit dates, messages related to consciousness raising, dramatic relief, environmental reevaluation and self-reevaluation were sent to smokers who had relapsed. Smokers who remained abstinent only received information based on PMT. To evaluate smokers' quitting intention, we used a 5-point scale ranging from not at all likely (1) to very likely (5) regarding the likelihood that they would try to quit in the next 6 months [3].
(Not all the participants had strong quitting intention. Some smokers did not want to quit smoking and only intended to reduce the amount of smoking or were curious about what a mobile cessation intervention is. Therefore, they expressed a desire to join this study, but may not have been at all likely to quit in the next six months) The WeChat application evaluated the PMT construct score by asking questions and recording information; then, it automatically calculated the lower score of the subcontent that needed to be strengthened. Specifically, the scale comprised 21 items using a 7-point Likert-type scale with responses ranging from 1 (definitely disagree) to 7 (definitely agree). Each construct subscale includes three items, and we computed the mean as the subscale score. We have published the details of this scale and evaluation process elsewhere [4][5]. A more detailed framework of the text and intervention based on the TTM and PMT is shown in Supplemental Table 1.

Development of the text bank
The second stage was to develop the intervention message bank. Messages were developed by Peking University, School of Public Health, with the input of smokers and smoking cessation professionals. Most of the core information came from official reports and publications, such as China reporting the health hazards of smoking, clinical guidelines for smoking cessation intervention in China, WHO reports on treating tobacco dependence in primary care and published research articles. An expert committee consisting of health education experts, smoking cessation experts, social medicine experts and IT experts was established. The committee assessed the quality of the messages, including whether the messages were scientific, motivating and acceptable.
The messages had a three-layer framework. The first layer was divided based on time and consisted of the prequit message (1-7 days), quit day message (8 days), withdrawal symptom management message (9-18), early quit message (19-36 days), and late period message (37-90 days). The second layer was divided based on the TTM. Before the quit day, messages were classified as 1. strong quitting intention or 2. weak quitting intention. After the quit day, messages were classified as 1. maintained abstinence and 2. relapsed. The third layer was divided based on PMT. Messages were classified as 1. increased severity and susceptibility; 2. decreased response cost and intrinsic and extrinsic rewards; and 3. increased self-efficacy and response efficacy. The core motivational messages consisted of 14 subgroups with a total of 200 text messages. There were also approximately 200 contact messages.
The last stage was to deploy the message library on the WeChat platform by using information technology. Our IT team completed the development process with several important considerations. First, the application needed to ensure confidentiality of the data. Second, the system needed to be user-friendly with ease for quick data entry. Third, there needed to be a back-end server to store the data. Fourth, the information needed to be presented in a way that could be easily read and interpreted.